Well, those links are to int2ext scripts - they work by moving most or all of your /data partition to a separate partition on your sd card. They require a reasonably fast and large sd card (partition shouldn't be more than ~20% of the total card space) and they can be notoriously picky about sd cards - old material will tell you that class 4 cards tend to have the highest random read/write speeds, but from what I've seen of newer cards speeds can vary wildly across manufacturers and even across different batches of seemingly identical cards
(SanDisk class4 cards still tend to be reliable afaik, but some new faster class cards aren't as useless as they used to be - old high class cards cause trouble though, most are not good at writing small files)
All int2ext scripts require that you boot the rom at least once (preferably twice) before flashing them.
They also require an sd-ext partition formatted to ext2/3/4
The roms in this thread don't contain another apps2sd or int2ext solution, so you can just flash one (the next boot will be longer)
Reverting int2ext solutions is rather difficult - make a nandroid first!
The Plus versions keep settings data on internal storage - more secure, faster if your sd card isn't very fast, less susceptible to bugs - but certain apps that like to consume space inside their app data directory (the default Android browser, for example) can make space management rather annoying...
Also, obijohn's scripts in this thread keep some very small bits of other information on internal storage - in theory this might help with some of the random bugs that tend to be associated with int2ext script usage on some setups, like random data drops and such...
(they're designed specifically for these roms, I think? I use them for other roms too, but changed a few things...)
(ejecting your SD card while the phone is running will also crash your phone when using these scripts)
If you have a slower SD card, or this all sounds far too complicated, you might consider try Link2SD instead - the essential functionality is similar, it moves apps to an sd-ext partition, and it has similar requirements to int2ext script usage, but it functions through an app lets you move individual apps to the sd-ext partition, rather than moving everything.
Link2SD isn't as difficult to revert... but you should still make a backup before trying any of this
(and apps on your sd card will be unavailable when it's ejected, but your phone shouldn't crash)